The most widespread hang-up methods use conventional devices of the cyma or overhanging counter-rail type, which comprise a horizontal support member onto which vertical rod members, generally made of a metallic material, are hooked, said rod members being provided with one or more hooks adjustable in height. Chains or other suspension means are also used. Most of these known devices are extremely flexible in use, and they are generally utilized in art-galleries and other showrooms. However they fail to offer a satisfactory solution of the security problem and the lighting problem.
The conventional lighting means are generally arranged for "overall lighting", i.e. for distributing the light rather uniformly over the entire wall surface, thus without taking into account the orientation of the different works of art to be shown, and, more particularly, their hang-up angle; furthermore, such arrangement does not take into account the either more or less reflecting nature of the surface of the works of art; consequently, in many show-rooms, which are apparently well lighted, the public is obliged to move to and fro for a considerable period of time in front of every work of art before a position is found from which the work of art can be viewed in a well-lighted condition without undesirable reflection--if such a position can be found at all.
It is noted that individual lighting of each work of art is difficult to achieve, since this method requires the provision of electric installations comprising loose wires and series of connecting devices or metal sections, which generally renders the arrangement entirely unaesthetic and involves fastidious mounting and adjusting operations.
According to another approach projectors are hooked onto, or suspended from the ceiling or beam members located at a certain distance from the hang-up wall; this solution provides for wide-angle lighting, except in the case where the projectors comprise an optical framing system which, while being quite expensive, provides for very precise lighting of a frame without lighting the environing wall. These devices are generally more or less stationary, and their number is very difficult to vary in function of the number of works of art to be exhibited. Furthermore this arrangement, when applied to large halls or galleries, requires the use of ladders or even scaffoldings for adjusting the lighting system. In addition it should be noted that the position of the light sources is not adjustable in most cases, unless considerable expense were involved, and consequently this solution does not overcome the problem of undesirable reflection effects. Furthermore it is known that for security reasons it has become increasingly necessary to provide glass panels in front of the works of art that have been left exposed to the open air up to now, which is the case of oil paintings, for example; this requirement brings about an amplification of the undesirable reflection effect. Now, in most museums and art-galleries visited by the public it is required that a plurality of persons be able to view one given painting without some of those persons being inconvenienced by undesirable reflection effects.
It is thus an object of the present invention to provide a unique device which complies with the hanging-up requirements as well as with the security and lighting requirements, remaining both reliable and flexible in use.
The device according to the invention uses a vertical suspension system including sliders displaceable along at least two metallic--and consequently electrically conductive--rails which are supplied with low-voltage electric current and isolated from each other, certain electrically isolated sliders allowing hanging up the works of art, while other sliders ensure the electric current supply of hinged arms which carry the low-voltage lighting system.
It should be noted that the "low-voltage current" is presently defined by specifications and rules which are in force in individual countries or groups of countries, the definition of this type of current being a matter of regulations rather than a technical matter. At any rate, the main characteristic of the low-voltage current resides in its harmlessness for humans or, in other words, in the fact that the related conductors may be employed with a very light isolation, or no isolation at all, without bringing about an electrocution hazard. This mode of low-voltage current supply by means of parallel, mutually isolated rails has been used on a large scale since electrical toys such as electric toy railways were introduced on the market.
The principle of low-tension (low-voltage) conductive metal sections is applied in many well-known lighting devices, which use, for example, double hinge bars isolated from each other and constituting at the same time an orientable support and electric current conducting means.
Thus in the E.E.C. countries an industry branch has developed which produces lighting systems supplied with 12 V current by means of small transformers included in the base or support of the lighting device, or with halogen-filled bulbs or tubes, the latter allowing, in addition, a lighting substantially equivalent to daylight to be obtained.
Halogen-filled lamps and tubes supplied with alternating or direct current are increasingly used, particularly in automotive vehicles and in stage-lighting systems (theater, cinema, television). They are more and more frequently adopted in the professional field (offices and the like), as well as in the domestic field (lighting of homes, gardens, etc.).